Mine roof supports

ABSTRACT

A support means for a cantilever of a mine roof support which cantilever includes two spaced parallel arms, comprising a bar located transversely of and beneath said two arms and adapted to urge said arms upwardly towards the mine roof, said bar being pivoted at approximately its mid-length about an axis parallel to the axes of said two arms, and means to urge said pivot bar upwardly, whereby said arms are able to extend upwardly to different extents due to the pivoting of said pivot bar.

United States Patent 1191 Smith MINE ROOF SUPPORTS [75] Inventor: David Beaumont Smith, Wakefield,

England [73] Assignee: Fletcher Sutcliiie Wild Limited [22] Filed: June 23, 1971 21 Appl. No.: 156,013

[30] Foreign Application Priority Data June 26, 1970 Great Britain 31,005/70 [52] US. Cl. 61/45 D, 248/357 [51] Int. Cl E2ld 15/45 [58] Field of Search 61/45 D; 91/170, 91/170 MP, 411, 412, 413, 414; 299/31, 33; 248/357 [56] References Cited UNITED STATES PATENTS 3,324,664 6/1967 Allen 61/45 D Groetschel 61/45 D 1451 Aug. 28, 1973 3,494,135 2/1970 Von Hippel 61/45 D 3,512,364 5/1970 Holland 61/45 D 3,534,559 10/1970 Seddon et ai. 61/45 D FOREIGN PATENTS OR APPLICATIONS 1,037,922 8/1966 Great Britain 61/45 D 1,180,955 l/l959 France 91/170 MP Primary EJ camineF-Dennis L. Taylor v Attorney- Allan M. Lowe and J. Ralph King et a1.

[ 7] ABSTRACT A support means for a cantilever of a mine roof support which cantilever includes two spaced parallel arms, comprising a bar located transversely of and beneath said two arms and adapted to urge said arms upwardly towards the mine roof, said bar being pivoted at approximately its mid-length about an axis parallel to the axes of said two arms, and means to urge said pivot bar upwardly, whereby said arms are able to extend upwardly to different extents due to the pivoting of said pivot bar.

4 Claims, 4 Drawing Figures Patented Aug. 28, 1973 3,754,402

2 Sheets-Sheet 1 Patented Aug. 28, 1973 3,754,402

2 Sheets-Sheet 2 MINE ROOF SUPPORTS This invention relates to mine roof supports and, in particular, to means for supporting a cantilever of a mine roof support which cantilever includes two spaced parallel arms, whether it be a fixed cantilever, a forepoling cantilever, or other known types.

Considering a support of the hydraulically powered self-advancing type e.g., as is commonly employed on a longwall mineral face relatively wide supports e.g., in excess of 18 inches have wide cantilevers, and torsional forces may be set up in the cantilever if one side thereof is in contact with a portion of the roof that projects downwardly from the general level of the roof or, conversely, if one side of the cantilever attempts to engage a hole or recess in the roof.

or pivot bar located transversely of and beneath the I two arms and adapted to urge the arms upwardly towards the mine roof, the bar being pivoted at approximately its mid-length about an axis parallel'to the axes of the two arms, and means to urge the pivot bar upwardly. I

Thus, in operation, although initially. the urge of the pivot bar on each arm is the same, the armsare able to extend upwardly to different extents due to the pivot bar pivoting about its axis when urging the arms upwardly and when roof problems previously outlined are encountered, so that the arms are in effect urgeddifferentially towards the roof.

6 and 7 in turn carry a roof engaging member constituted by two spaced parallel arms 8 that are pivotally attached, one to each side, of the canopy means 7 on pivot pins 9 and slidably supported by the canopy gether at their forward ends by a cover plate 10.

The arms 8 are urged upwardly by a pivot barll located beneath the arms, the bar being provided at its point of contact with each arm 8 with wear pads and, beyond each arm 8, with side members 12 to retain each arm 8 on the pivot bar 11. At its mid-position the pivot bar 11 is pivotally attached, about an axis that is parallel to that of the arms 8, to a pivot shaft 13, carried by a fabricated cantilever bracket indicated generally The cantilever bracket 14 is pivotally attached to the canopy means 6 by transversely extending pins 21.

The cantilever bracket 14 includes two pairs of pivot brackets 15, 16, one pair located towards each side of thecantilever bracket and welded to two transversely extending angle irons l7, 18, through apertures in which one end of the pivot shaft 13 passes, to be secured by a pin 19. Adjacent the canopy means 6 are holes 20 in the upper ends of the pivot brackets l5, 16 through which two co-axial pivot pins 21 pass, by which the cantilever bracket is pivotally attached to the roof support. The pins 21 pass through apertured brackets 22 that extend forwardly from the canopy means 6. The lower end of the pivot brackets 15, 16 carry slotted brackets 23, 24 which constitute means for pivotal attachment to each and hence to the cantilever bracket The invention may be readily applied to the cantile- I ver of a support of any of the types mentioned above.

In detail, the pivot bar may be pivotally located on one end of a pivot shaft, carried by a fabricated cantilever bracket, the latter being provided at each side and adjacent the support with attachment means'for two co-axial pivot pins, and generally beneath these means, with means for pivotal attachment to the cantilever bracket of the free end of a piston rod of a pressure capsule, the cylinder of each capsule being pivotally attached to an upper part of the front of the roof support. It is of course equally possible to apply the support means of the invention to a cantilever extending rearwardly from the rear of a roof support.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a side elevation of a poweredself-advancing mine roof support;

FIG. 2 is a plan view in the direction of arrowA of a portion of FIG. 1;

FIG. 3 is a side elevation of FIG. 2; and,

FIG. 4 is a front elevation of FIG.'2.

In FIG. 1, the mine roof support can be seen to comprise a forward chock leg I mounted on a base means 2 and a pair of rearward chock legs 3 (one only visible) mounted on a base means 4, the two base means being interconnected by a pair of double-acting advancing rams 5 one only visible.

At their upper ends, the chock leg 1 carries a roof contacting canopy means 6 while the chock legs 3 carry a roof contacting canopy means 7. The canopy means of the free end of a piston 25 of a pressure capsule 26 located beneath the canopy means 6 and one to each side of the chock leg 1, the cylinder 27 of each pressure capsule being pivotally supported at its rearward end by a pivot pin 28 passing through a bracket 29 depending downwardly from the canopy means 6.

The roof support operates in a well known manner, while the pivot bar arrangement according to the present invention, for supporting the cantilever portion of the arms 8, enables the arms 8 to extend automatically upwardly to different extents should roof conditions make this necessary.

What is claimed is:

1. A mine roof support including a main support means for supporting a cantilever section of said mine roof support and urging said cantilever section to the mine roof, which cantilever section comprises at least two spaced parallel longitudinally extending arms each pivotally attached to said main support means said support means comprising a bracket secured to the main support means by transverse pivots and hydraulic ram means carried by an upper part of said support means bracket, said bar being pivotally attached at approxithe same time allowing pivoting action to accommodate side-to-side variation in the mine roof height.

2. A mine roof support as claimed in claim 1, wherein said hydraulic ram means comprises two pressure cappiston rods.

3. A mine roof support as claimed in claim 1, wherein two pairs of pivot brackets are included in said cantilever bracket, one pair of said pivot brackets located towards each side of said cantilever bracket, and two angle irons welded to said pivot brackets.

4. A mine roof support as claimed in claim 3, wherein said angle irons have apertures through which passes one end of said pivot shaft. 

1. A mine roof support including a main support means for supporting a cantilever section of said mine roof support and urging said cantilever section to the mine roof, which cantilever section comprises at least two spaced parallel longitudinally extending arms each pivotally attached to said main support means said support means comprising a bracket secured to the main support means by transverse pivots and hydraulic ram means carried by an upper part of said support means and operatively attached to said bracket to pivot the same about said transverse pivots, and a support bar engaging the underside of both said parallel arms, and a longitudinally extending shaft attached to said bracket, said bar being pivotally attached at approximately its mid-length to the free end of said pivot shaft, the longitudinal axis of said pivot shaft running parallel to said arms, said pivot shaft being substantially rigid, whereby support to said roof is provided by said cantilever section through said main support means while at the same time allowing pivoting action to accommodate side-to-side variation in the mine roof height.
 2. A mine roof support as claimed in claim 1, wherein said hydraulic ram means comprises two pressure capsules, with a piston rod extending from each end of said capsules, a cylinder of each of said capsules being pivotally attached to an upper part of said roof support, each capsule being located generally beneath said attachment means, and means for pivotal attachment to said cantilever bracket of the free end of each of said piston rods.
 3. A mine roof support as claimed in claim 1, wherein two pairs of pivot brackets are included in said cantilever bracket, one pair of said pivot brackets located towards each side of said cantilever bracket, and two angle irons welded to said pivot brackets.
 4. A mine roof support as claimed in claim 3, wherein said angle irons have apertures through which passes one end of said pivot shaft. 